Numerous aldehydic compounds are known in the art. For instance, dec-2-en-1-al is employed in the reconstitution of flavours of fruity type, especially of citrus-fruits, or in the manufacture of peach type aromas. Certain lower alkyl, .alpha.,.beta.-unsaturated aldehydes, such as hex-2-en-1-al, namely in its trans isomeric form, is used in compositions of strawberry, banana, apple or apricot type. Other unsaturated aldehydes having the double bond in the .beta.,.gamma.- or .gamma.,.delta.-position find an advantageous utilization in the reconstitution of creamy and fatty notes. Hept-4-en-1-al belongs to this class of derivatives.
U.S. Pat. No. 3,914,451 describes the use as flavouring ingredient of 2-butyl-but-2-en-1-al, a compound possessing a gustative taste of sweet, slightly roasted and fatty character reminiscent of hazelnuts.